"In a Glass Darkly" by J. Sheridan Le Fanu is a collection of supernatural tales, with the first volume focusing on the story of Mr. Jennings, a clergyman plagued by a mysterious and malevolent presence. The narrative is presented through the perspective of Dr. Martin Hesselius, a German physician with a keen interest in metaphysical medicine. Mr. Jennings recounts his experiences with a spectral monkey that haunts him, appearing at various times and places, and exerting a malevolent influence over his thoughts and actions. This presence disrupts his life, particularly his religious duties, and drives him to the brink of despair. Despite seeking medical advice and attempting various remedies, the apparition persists, leading Jennings to fear for his sanity and soul. Dr. Hesselius listens to Jennings' account with a mix of scientific curiosity and empathy, promising to investigate the case further. The story explores themes of psychological disturbance, the intersection of the spiritual and material worlds, and the limits of human understanding in the face of the supernatural.